Field of the Disclosure
This disclosure relates to a grinding apparatus and an adaptive method for the fabrication of a liquid crystal display device that is able to improve an adsorption defect of a substrate onto a substrate stage.
Description of the Related Art
Recently, various flat display devices of reduced weight and bulk, unlike cathode ray tubes, are becoming popular. Such flat display devices include liquid crystal display devices, field emission displays, plasma display panels and organic electro luminescence display devices.
Flat panel display devices like these are included in image display devices such as televisions and computer monitors, and play the role of displaying various images and characters as well as motion pictures.
Among these flat panel display devices, liquid crystal display devices are used in many applied fields because of it is desirable to make electronic appliances light, thin, short and small and because their mass productivity has improved.
In particular, an active matrix type liquid crystal display device that drives liquid crystal cells by use of thin film transistors has the advantages of an excellent picture quality and low power consumption. In addition, these devices are rapidly being developed to be larger and to have high resolution. This is the result of research and development and due to recent mass production technology.
The fabrication of a liquid crystal display device involves various processes: a process of fabricating a thin film transistor substrate whereby the thin film transistor is formed by pixels to be a switching device; a process of fabricating a color filter substrate that faces the thin film transistor substrate and in which a common electrode and red, green and blue color filters are formed in correspondence to each pixel; and a cell process of bonding two substrates together after interposing liquid crystal between the thin film transistor substrate and the color filter substrate that were fabricated by the above two processes. A liquid crystal display panel is completed by the cell process and the liquid crystal display device is completed by adhering a polarizing plate, a drive circuit substrate and a backlight unit to the liquid crystal display panel.
The cell process that completes the liquid crystal display panel by bonding the thin film transistor and the color filter substrate together will now be briefly explained.
The cell process can be divided into an alignment process, a cell gap forming process, a cell cutting process, a liquid crystal injection process, and a grinding process. During the alignment process, the liquid crystal is aligned in one direction in the thin film transistor substrate where the thin film transistors are arranged and in the color filter substrate where the color filter is formed. During the cell gap forming process, the two substrates which went through the alignment process are bonded together with a fixed gap maintained. In the cell cutting process, a circular plate panel bonded by the cell gap forming process is cut into unit panels. During the liquid crystal injection process, liquid crystal is injected into the inside of each unit panel. In the grinding process the cut surface is ground.
The grinding process involves grinding a cut edge of the liquid crystal display panel after the liquid crystal is injected. This is to prevent an operator from being injured by a sharp cut surface. It also prevents a signal input pattern and a printed circuit board from being misaligned, and a crack from forming by a process impact when drive IC's and a printed circuit board for applying drive signals to data lines and gate lines formed on the thin film transistor substrate and a signal input pattern for inputting drive signals are adhered to the upper surface of the side of an array substrate by use of ACF (anisotropic conductive film) bonding or soldering.
FIG. 1 is a planar view illustrating a substrate stage that supports a liquid crystal display panel in a grinding apparatus for the fabrication of a general liquid crystal display device.
The grinding apparatus for the fabrication of the liquid crystal display device includes a substrate stage 20 that adsorbs and fixes the liquid crystal display panel to be ground.
The substrate stage 20 includes a plurality of vacuum adsorption holes 21 for adsorbing the liquid crystal display panel.
The vacuum adsorption hole 21 plays the role of fixing the liquid crystal display panel to the substrate stage 20 by use of vacuum adsorption.
However, the grinding apparatus for the fabrication of the general liquid crystal display device has a problem: impurities such as glass powder generated by grinding the edge of the liquid crystal display panel are piled up in the vacuum adsorption hole 21 and can clog the adsorption hole 21 so as to generate a substrate adsorption defect during the process.